package main

import "fmt"

func main() {
	fmt.Println("hello, world.")
}

func Join(elems []string, sep string) string {
	switch len(elems) {
	case 0:
		return ""
	case 1:
		return elems[0]
	}

	result := elems[0]
	for _, e := range elems {
		result += sep + e
	}
	return result
}
